In the U.S. Pat. No. 6,951,403 B2 a device for illuminating a generally flat surface is described, which comprises a battery operated light source contained within a housing to which a transparent light conductive illuminating body is mounted. The device may be placed with the illuminating body over a book or other flat surfaces for illuminated viewing through the transparent illuminating body. The illuminating body is tapered in a wedge shape to deflect the conducted light onto the underlying surface. Unfortunately, the described device is less convenient for reading books, which possess in general a curved reading area. The interaction of the curved reading area with the tapered illuminating body leads to a deformed image of the illuminated page. In addition, the device is a relatively thick wedge shaped light guide where the thickness results in relatively high weight and this reduces ease of use. It also results in a relatively high mechanical stiffness making it very difficult to bend the device over a curved reading area.
Furthermore, there are magnification lenses known, which can be clipped onto the illumination devices described above. Unfortunately, such magnification elements possess a relatively small magnification. Another option to optically magnify a surface is to use a bar magnifier. This bar magnifier is often an acrylic body, possessing a curved top surface and thereby optically magnifying the surface on which the bar magnifier is lying. The disadvantage of such bar magnifier is their weight and the distortion of the image.